Liquid-operated brake for motor vehicles



March 26, 1929. F N c 1,706,394 LIQUID OPERATED BRAKE FOR MOTOR vamcngs Filed Feb. 28, 1823 2 Sheets-Sheet URIHIH I INVENTOR 63110 0 Jarndtfl ATTORNEY March 26, 1929. G, FORNACA 1,706,394

LIQUID OPERATED BRAKE FOR MOTOR VEHICLES Filed Feb. 28, 1923 2 Sheets-Sheet 2 INVENTOR d an? 1 9/7240.

So. 4 Gear- 4v it? ATTORNEY Patented Mar. 26, 1929.-

PATENT OFFICE.

GUIDO FORNAGA, or TUBIN, ITALY.

LIQUID-OPERATED BRAKE FOR MOTOR VEHICLES.

Application filed February 28, 1923, Serial No. 621,747, and in Italy February 28, 1922.

This invention relates to liquid operated brakes for motor vehicles in which the movement of the engine itself furnishes the necessary braking energy.

Under the present invention the brake pump and brake cylinders are disposed in the gear box, and the lubricating Oll s'ervmg to lubricate the speed gear is used as the means of transmission of energy between the pump and the. brake cylinders. In the form of my invention herein disclosed, the pump normal- 1y runs idly taking oil from the body of 011 in the gear case and returning it thereto. The discharge passage from the pump l 5vwith a manually operated-valve which may be moved to restrict or close the passage between the discharge side of the pump and the body of oil in the gear case. When this valve is operated to restrict or shut off the flow of oil, pressure is created at the discharge side of the pump and this forces 011 into the brake cylinders and operates the brakes.

The improved brake operating means designed in accordance with my invention is simple and inexpensive inv construction. It

, consists of a few parts, all of which are readily made and assembled. The parts when assem led are readily accessible for repair or adjustment and the device as a whole is durable and economical and eflicient in operatlon.

In orderthat the invention may be more clearlyunderstood, reference is made to the annexed drawing which shows by wayof example one embodiment'of the invention, and in which:

, Fig. 1 is a transverse section of the pump,

Fig. 2 is a longitudinal section on the hne 22, Fig. 1, Fig. 3 is a of Fig. 2

Referring tothe drawing, the transmission case or gear box 10 is divided by means of a sectional plan on the line 3-3 vertical partition 11 into a transmission compartment 12 and a pumping compartment 13. The transmission compartment contalns the transmission gears 15 carried by shafts 17, journaled in the partition 11. Cast integrally with the bottom of the gear box are two brake operating cylinders 20 and 20, which are connected by a portion 21 formed with a trans- .verse passage 22 communicating with the 1nterior of the cylinders 20 and 20 at points approximately midway between their ends, and also with a passage 23 which extends as shown from the face of the casting to the pas sage 22. The cylinders 20 and 20 and the is provided tion 11 and-a cover plate 27 secured to the casting 26. Journaled in the casing are pump gears 29 and 30, the'gear 29 being keyed to and operated by thetransmission shaft.

The oil in the gear box which is primarily intended for the lubrication of the gears, is also used, as mentioned, for the purpose of transmitting the energy from the pump to the brake. It is sucked up from the body of oil 31 in the compartment 13 through passage 33* and discharged into ,the chamber 34, where valves 35 and 36 are situated. The valve 35 is hand or foot operated by means of an internal'lever 37 secured to a shaft38 and an external lever 39 likewise secured to the shaft 38 outside of the gear box. Oil passing through the valve 35 when in its normal or non-braking position, passes through a discharge opening 40 back to the. body of oil in the gear box as indicated by the arrow X in Figure 1. Leading from the chamber 34 to the passage 23 in the portion 21 of the gear box casting is a passage 42 through which oil is forced for the purpose of operating the brakes when the valve 35 has been moved to close'or restrict the return flow of oil to the gear box. Valve 36 is a'safety valve and acts as requiredby regulating the tension of the spring 44 by means of a guide 45 and a locknut 46, to prevent an excessive rise of pressure on the discharge side of the pump. As will be seen from Fig. 1, both valves 35 and 36 are removable through the top of the pump casing without the necessity of disturbing the other parts of the brake operating means.

The brakes are operated by four pistons, 45, 50, 45 and located as shown in the cylinders 20 and 20 on opposite sides'of the passage 22. The pistons in each cylinder havepiston rods extending through opposite ends of the cylinder and these rods are connected by suitable levers and bars to the brakes. The construction shown is particularly adapted for use with a vehicle having four brakes, one for each road wheel, in which case each of the brakes will be actuated by one of the pistons. The operation .of the invention is as follows:

Normally,-the oil is sucked up by the pump through the passage 33 and discharged into the chamber 34, from which it passes through the open valve 35 and returns to the gear box through the discharge opening 40. Under these circumstances, the resistance offered by the opening and opening at the valve 35 being practically nil, the pressure in the passages 42, 23 and 22 and in the cylinders 20 and 20' is also practically nil and as a result, no movement of the pistons takes place. When the valve 35 is moved to restrict the passage of oil through its opening, the pressure in the passages 42, 23 and 22 and in the cylinders 20 and 20' increases in proportion so that the pistons are caused to move, the space between the pistons being continually supplied with oil by the pump.

It will be noted that the pump which com prises the gears, casing and valves, is screwed or bolted to the artition 11 of the gear box and is complete y enclosed in the compart-' enables him to adjust the position of the valve scribed" without departing from the scope of accordingly.

It is of course, possible to vary the details embodied in the construction of the device dethis invention.

Having now particularly described and ascertained the nature of my invention and in what manner the same is to be performed, I claim: I

1. In a. motor vehicle having brakes, a transmission casing containing lubricating oil, a transmission shaft in said casing, a bralre operating cylinder, a piston therein 'havmg a rod extendingithrough on end thereof, said cylinder being rigid with said casing and submerged in the-oil therein, a pump in said casing operated from sa d shaft and connections whereby said pump Ireceives oil from said casing and delivers it to said cylinder to operate the brakes.

2. In a motor vehicle, a' transmission shaft and a transmission casing containing a body of lubricating oil, brake operating means submerged in the oil in said casing, said means comprising a brake cylinder ri d. with said casing and apiston in said cylin er, operating. connections from said piston comprising a piston rod extending through one end ofsaid cylinder into the body of oil ,in'said casmg,

--said cylinder .end having communication with said casing. and means'ope'rated from said-shaft for drawing oil from the'body of "cured to the lower part said casing.

Q venting oil in said casing and delivering it to said cylinder .for moving said piston.

3. In amotor vehicle, a transmissionshaft and casing, a brake cylinder in said casing and integral with bottom thereof, a vertical partitionin said casing formed in part by said; brake cylinder and a gear pump secured to .in the other of said compartments operated.

from said transmission, a brake cylinder seextending along the bottom of said transmission compartment and connections .to said pump whereby the pump receives oil from said casing and delivers it to said cylinder.

5. a motor vehicle, a casing adapted to contain oil, a partition dividin into two compartments, transmission in one of said compartments, a pump in the other of said compartments operated from said transmission, a brake cylmdersecured to the lower part of said partition and cast integrally with the bottom of said casing.

6. Ina motor vehicle,

gearing said casing into two compartments, transof said partition and said casing said partition and operated from said shaft a casing adapted to containoil, a transverse partition dividing missiongearing in one of said compartments journaled insald parti ion, twovbrak'e cylinders formed integrally with the bottom of said casing and extending from said partition intosaid transmission compartment, two spaced pistons in each of said cylinders having rods extending through opposite ends of the cylinder, brake operating connections for each rod, 8. gear pump. in the other of said compartments, said pump bein secured to said partition and being driven rom said gearing, said pump having an inlet'passage communicating with the interior of said cas-- ing and an outlet passage communicating with the space between the pistons of each cylinder and manuall operated means for restricting the return ow from said pump to 7 In a motor vehicle, a. transmission (:as-' ing having brake cylinders cast integrally with the bottom thereof and ada ted to. have their ends submerged in the In in said casing, cylinder,

ricating oil two spaced pistons in eachv said casing being formed with a pas-' sage joining the space between the pistons and 5 apassage communicating with said. first named passage and a pump'in casing having an inlet in communication withthe interior of said casing and an outlet communicating with said last named passage, and means for said outlet to the interior of said mg formed 8.. In a motor vehicle, a transmission casing having'a wall and a transmission shaft 'ournaled therein, a gear pump in said casof a casting of generally flat form secured to said wall and a cover plate secured to said casting, pump gears journaled in said casting and'plate, one of-said gearsbeing mounted upon and operated by said transmission shaft, said pump having an outlet and a downwardly extending intake passage adapted to draw oil continuously from said casing wheneversaid pump gears are rotating, a reciprocating control valve in said outlet removably mounted in said casing and brake operating means communicating with said outlet.

9. In a motor vehicle, transmission gear-- ing, a casing having a vertical'wall formed in part by a brake operating cylinder and having a passage extending from the face of said wall to said cylinder, a transmission shaft extending through said wall above said cylinder, a gear pump having a casing secured against said wall and formed with an outlet passage communicating with the passage .in said wall and having pump gears, one of I which is mounted on said shaft and a control to the interior of said brake cylinder, a brake operating piston in said cylinder, a gear pump in said casing, comprising a casting of generally flat form secured against the said face of said partition, said gear pump easting being formed with an inlet passage adapted to receive oil from the lower portion of said casing, and an outlet passage terminating at the said face of said partition and communicating at that point with the bore in said first named. casting, said gear pump casting being formed at-its upper portion with an opening which places said outlet passa e in free communication with the inter or of said casing outside said pump, and manual means for closing said opening.

In witness whereof, I have hereunto signed my name.

1m. GUIDO FORNACA. 

